Radio frequency communication systems with discrete time cancellation for coexistence management

ABSTRACT

Radio frequency (RF) communication systems with coexistence management are provided herein. In certain embodiments, a mobile device includes a first antenna, a first front end system that receives an RF receive signal from the first antenna, a first transceiver coupled to the first front end system, a second antenna, a second front end system that provides an RF transmit signal to the second antenna, and a second transceiver coupled to the second front end system. The second front end system observes the RF transmit signal to generate an RF observation signal, which is downconverted and processed by the second transceiver to generate digital observation data that is provided to the first transceiver. The first transceiver downconverts the RF receive signal to baseband, and compensates the baseband receive signal for an amount of RF signal leakage indicated by the digital observation data.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. § 119 ofU.S. Provisional Patent Application No. 62/720,584, filed Aug. 21, 2018,and titled “RADIO FREQUENCY COMMUNICATION SYSTEMS WITH DISCRETE TIMECANCELLATION FOR COEXISTENCE MANAGEMENT,” which is herein incorporatedby reference in its entirety.

BACKGROUND Field

Embodiments of the invention relate to electronic systems, and inparticular, to radio frequency electronics.

Description of Related Technology

Radio frequency (RF) communication systems can be used for transmittingand/or receiving signals of a wide range of frequencies. For example, anRF communication system can be used to wirelessly communicate RF signalsin a frequency range of about 30 kHz to 300 GHz, such as in the range ofabout 410 MHz to about 7.125 GHz for fifth generation (5G) frequencyrange 1 (FR1) communications.

Examples of RF communication systems include, but are not limited to,mobile phones, tablets, base stations, network access points,customer-premises equipment (CPE), laptops, and wearable electronics.

SUMMARY

In certain embodiments, the present disclosure relates to a mobiledevice. The mobile device includes a first antenna, a second antenna, afirst front end system configured to process a radio frequency receivesignal from the first antenna, and a first transceiver configured tofurther process the radio frequency receive signal to generate a firstdigital baseband receive signal. The first transceiver includes adiscrete time cancellation circuit configured to compensate the firstdigital baseband receive signal for radio frequency signal leakage basedon digital observation data. The mobile device further includes a secondfront end system configured to process a radio frequency transmit signalfor transmission on the second antenna, and to generate a radiofrequency observation signal based on observing the radio frequencytransmit signal, and a second transceiver configured to process theradio frequency observation signal to generate the digital observationdata, and to provide the digital observation data to the firsttransceiver.

In some embodiments, the discrete time cancellation circuit includes aspectral regrowth modeling circuit configured to estimate an amount ofaggressor spectral regrowth present in the radio frequency receivesignal based on the digital observation data. According to a number ofembodiments, the spectral regrowth modeling circuit is configured toestimate the amount of aggressor spectral regrowth based on modelingadjacent channel leakage ratio using predistortion.

In several embodiments, the second transceiver is configured to generatea digital observation signal based on the radio frequency observationsignal, and the second transceiver includes a baseband sampling circuitconfigured to sample the digital observation signal to generate thedigital observation data. According to various embodiments, the basebandsampling circuit generates the digital observation data to reflect anamount of direct transmit leakage present in the radio frequencytransmit signal.

In some embodiments, the second front end system includes a directionalcoupler configured to generate the radio frequency observation signal.According to a number of embodiments, the directional coupler generatesthe radio frequency observation signal based on a forward coupled pathto the second antenna.

In several embodiments, the first front end system is a cellular frontend system and the second front end system is a WiFi front end system.

In various embodiments, the first front end system is a WiFi front endsystem and the second front end system is a cellular front end system.

In a number of embodiments, the second transceiver is configured tocompensate a second baseband receive signal for radio frequency signalleakage based on additional digital observation data from the firsttransceiver. According to several embodiments, the first transceiver isconfigured to receive a sensed radio frequency signal from a directionalcoupler of the first front end system, and to process the sensed radiofrequency signal to generate the additional digital observation dataprovided to the second transceiver. In accordance with severalembodiments, the first front end system includes a duplexer, thedirectional coupler positioned between an output of the duplexer and thefirst antenna. According to some embodiments, the first front end systemincludes a duplexer and a power amplifier, and the directional coupleris positioned between an output of the power amplifier and an input tothe duplexer.

In certain embodiments, the present disclosure relates to a transceiverincluding a receive channel configured to process a radio frequencyreceive signal to generate a digital baseband receive signal, anobservation channel configured to process a radio frequency observationsignal to generate a digital observation signal, a baseband samplingcircuit configured to sample the digital observation signal to generatefirst digital observation data, an output configured to output the firstdigital observation data, an input configured to receive second digitalobservation data, and a discrete time cancellation circuit configured tocompensate the digital baseband receive signal for radio frequencysignal leakage based on the second digital observation data.

In various embodiments, the discrete time cancellation circuit includesa spectral regrowth modeling circuit configured to estimate an amount ofaggressor spectral regrowth present in the radio frequency receivesignal based on the second digital observation data. According to anumber of embodiments, the spectral regrowth modeling circuit isconfigured to estimate the amount of aggressor spectral regrowth basedon modeling adjacent channel leakage ratio using predistortion.

In several embodiments, the second digital observation data indicates anamount of direct transmit leakage present in an aggressor radiofrequency transmit signal.

According to a number of embodiments, the transceiver further includes atransmit chancel configured to generate a radio frequency transmitsignal.

In a number of embodiments, the transceiver is implemented as a cellulartransceiver.

In several embodiments, the transceiver is implemented as a WiFitransceiver.

In certain embodiments, the present disclosure relates to a method ofcoexistence management in a mobile device, the method includingproviding a radio frequency receive signal from a first front end systemto a first transceiver, processing the radio frequency receive signal togenerate a first digital baseband receive signal using the firsttransceiver, compensating the first digital baseband receive signal forradio frequency signal leakage based on digital observation data using adiscrete time cancellation circuit of the first transceiver, generatinga radio frequency observation signal based on observing a radiofrequency transmit signal using a second front end system, andprocessing the radio frequency observation signal to generate thedigital observation data using a second transceiver.

In various embodiments, the method further includes providing thedigital observation data from the second transceiver to the firsttransceiver.

In a number of embodiments, the method further includes compensating thefirst digital baseband receive signal includes estimating an amount ofaggressor spectral regrowth present in the radio frequency receivesignal based on the digital observation data using a spectral regrowthmodeling circuit. According to several embodiments, estimating theamount of aggressor spectral regrowth includes modeling adjacent channelleakage ratio using predistortion.

In various embodiments, processing the radio frequency observationsignal to generate the digital observation data includes generating adigital observation signal based on the radio frequency observationsignal, and sampling the digital observation signal to generate thebaseband observation data. In according with a number of embodiments,the method further includes generating the digital observation data toreflect an amount of direct transmit leakage present in the radiofrequency transmit signal.

In several embodiments, the method further includes generating the radiofrequency observation signal using a directional coupler of the secondfront end system.

In some embodiments, the first front end system is a cellular front endsystem and the second front end system is a WiFi front end system.

In a number of embodiments, the first front end system is a WiFi frontend system and the second front end system is a cellular front endsystem.

In various embodiments, the method further includes compensating asecond baseband receive signal of the second transceiver for radiofrequency signal leakage based on additional digital observation datafrom the first transceiver.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of one example of a mobile devicecommunicating via cellular and WiFi networks.

FIG. 2 is a schematic diagram of one example of signal leakage for an RFcommunication system.

FIG. 3A is a schematic diagram of one example of direct transmit leakagefor an RF communication system.

FIG. 3B is a schematic diagram of one example of regrowth leakage for anRF communication system.

FIG. 4A is a schematic diagram of an RF communication system withcoexistence management according to one embodiment.

FIG. 4B is a schematic diagram of an RF communication system withcoexistence management according to another embodiment.

FIG. 5 is a schematic diagram of an RF communication system withcoexistence management according to another embodiment.

FIG. 6 is a schematic diagram of an RF communication system withcoexistence management according to another embodiment.

FIG. 7 is a schematic diagram of an RF communication system withcoexistence management according to another embodiment.

FIG. 8 is a schematic diagram of one embodiment of a mobile device withcoexistence management.

FIG. 9A is a schematic diagram of one embodiment of a packaged modulewith coexistence management.

FIG. 9B is a schematic diagram of a cross-section of the packaged moduleof FIG. 9A taken along the lines 9B-9B.

DETAILED DESCRIPTION OF EMBODIMENTS

The following detailed description of certain embodiments presentsvarious descriptions of specific embodiments. However, the innovationsdescribed herein can be embodied in a multitude of different ways, forexample, as defined and covered by the claims. In this description,reference is made to the drawings where like reference numerals canindicate identical or functionally similar elements. It will beunderstood that elements illustrated in the figures are not necessarilydrawn to scale. Moreover, it will be understood that certain embodimentscan include more elements than illustrated in a drawing and/or a subsetof the elements illustrated in a drawing. Further, some embodiments canincorporate any suitable combination of features from two or moredrawings.

FIG. 1 is a schematic diagram of one example of a mobile device 2 acommunicating via cellular and WiFi networks. For example, as shown inFIG. 1, the mobile device 2 a communicates with a base station 1 of acellular network and with a WiFi access point 3 of a WiFi network. FIG.1 also depicts examples of other user equipment (UE) communicating withthe base station 1, for instance, a wireless-connected car 2 b andanother mobile device 2 c. Furthermore, FIG. 1 also depicts examples ofother WiFi-enabled devices communicating with the WiFi access point 3,for instance, a laptop 4.

Although specific examples of cellular UE and WiFi-enabled devices isshown, a wide variety of types of devices can communicate using cellularand/or WiFi networks. Examples of such devices, include, but are notlimited to, mobile phones, tablets, laptops, Internet of Things (IoT)devices, wearable electronics, customer premises equipment (CPE),wireless-connected vehicles, wireless relays, and/or a wide variety ofother communication devices.

In certain implementations, UE, such as the mobile device 2 a of FIG. 1,is implemented to support communications using a number of technologies,including, but not limited to, 2G, 3G, 4G (including LTE, LTE-Advanced,and LTE-Advanced Pro), 5G NR, WLAN (for instance, WiFi), WPAN (forinstance, Bluetooth and ZigBee), WMAN (for instance, WiMax), and/or GPS.In certain implementations, enhanced license assisted access (eLAA) isused to aggregate one or more licensed frequency carriers (for instance,licensed 4G LTE and/or 5G NR frequencies), with one or more unlicensedcarriers (for instance, unlicensed WiFi frequencies).

Furthermore, certain UE can communicate not only with base stations andaccess points, but also with other UE. For example, thewireless-connected car 2 b can communicate with a wireless-connectedpedestrian 2 d, a wireless-connected stop light 2 e, and/or anotherwireless-connected car 2 f using vehicle-to-vehicle (V2V) and/orvehicle-to-everything (V2X) communications.

Although various examples of communication technologies have beendescribed, mobile devices can be implemented to support a wide range ofcommunications.

Various communication links have been depicted in FIG. 1. Thecommunication links can be duplexed in a wide variety of ways,including, for example, using frequency-division duplexing (FDD) and/ortime-division duplexing (TDD). FDD is a type of radio frequencycommunications that uses different frequencies for transmitting andreceiving signals. FDD can provide a number of advantages, such as highdata rates and low latency. In contrast, TDD is a type of radiofrequency communications that uses about the same frequency fortransmitting and receiving signals, and in which transmit and receivecommunications are switched in time. TDD can provide a number ofadvantages, such as efficient use of spectrum and variable allocation ofthroughput between transmit and receive directions.

Different users of the illustrated communication networks can shareavailable network resources, such as available frequency spectrum, in awide variety of ways. In one example, frequency division multiple access(FDMA) is used to divide a frequency band into multiple frequencycarriers. Additionally, one or more carriers are allocated to aparticular user. Examples of FDMA include, but are not limited to,single carrier FDMA (SC-FDMA) and orthogonal FDMA (OFDMA). OFDM is amulticarrier technology that subdivides the available bandwidth intomultiple mutually orthogonal narrowband subcarriers, which can beseparately assigned to different users.

Other examples of shared access include, but are not limited to, timedivision multiple access (TDMA) in which a user is allocated particulartime slots for using a frequency resource, code division multiple access(CDMA) in which a frequency resource is shared amongst different usersby assigning each user a unique code, space-divisional multiple access(SDMA) in which beamforming is used to provide shared access by spatialdivision, and non-orthogonal multiple access (NOMA) in which the powerdomain is used for multiple access. For example, NOMA can be used toserve multiple users at the same frequency, time, and/or code, but withdifferent power levels.

Examples of Radio Frequency Systems with Coexistence Management

Radio frequency (RF) communication systems can include multipletransceivers for communicating using different wireless networks, overmultiple frequency bands, and/or using different communicationstandards. Although implementing an RF communication system in thismanner can expand functionality, increase bandwidth, and/or enhanceflexibility, a number of coexistence issues can arise between thetransceivers operating within the RF communication system.

For example, an RF communication system can include a cellulartransceiver for processing RF signals communicated over a cellularnetwork and a wireless local area network (WLAN) transceiver forprocessing RF signals communicated over a WLAN network, such as a WiFinetwork. For instance, the mobile device 2 a of FIG. 1 is operable tocommunicate using cellular and WiFi networks.

Although implementing the RF communication system in this manner canprovide a number of benefits, a mutual desensitization effect can arisefrom cellular transmissions interfering with reception of WiFi signalsand/or from WiFi transmissions interfering with reception of cellularsignals.

In one example, cellular Band 7 can give rise to mutual desensitizationwith respect to 2.4 Gigahertz (GHz) WiFi. For instance, Band 7 has anFDD duplex and operates over a frequency range of about 2.62 GHz to 2.69GHz for downlink and over a frequency range of about 2.50 GHz to about2.57 GHz for uplink, while 2.4 GHz WiFi has TDD duplex and operates overa frequency range of about 2.40 GHz to about 2.50 GHz. Thus, cellularBand 7 and 2.4 GHz WiFi are adjacent in frequency, and RF signal leakagedue to the high power transmitter of one transceiver/front end affectsreceiver performance of the other transceiver/front end, particularly atborder frequency channels.

In another example, cellular Band 40 and 2.4 GHz WiFi can give rise tomutual desensitization. For example, Band 40 has a TDD duplex andoperates over a frequency range of about 2.30 GHz to about 2.40 GHz,while 2.4 GHz WiFi has TDD duplex and operates over a frequency range ofabout 2.40 GHz to about 2.50 GHz. Accordingly, cellular Band 40 and 2.4GHz WiFi are adjacent in frequency and give rise to a number ofcoexistence issues, particularly at border frequency channels.

Desensitization can arise not only from direct leakage of an aggressortransmit signal to a victim receiver, but also from spectral regrowthcomponents generated in the transmitter. Such interference can lierelatively closely in frequency with the victim receive signal and/ordirectly overlap it. Although a receive filter can provide somefiltering of signal leakage, the receive filter may provide insufficientattenuation of the aggressor signal, and thus the sensitivity of thevictim receiver is degraded.

Conventional techniques alone are insufficient for providing mutualcoexistence. In one example, a very high quality-factor (high Q)bandpass filter (for instance, an acoustic bandpass filter) can beincluded at the output of a power amplifier of an aggressor transmitterto attenuate spectral regrowth. When the attenuation provided by thefilter is sufficiently high, the victim receiver may not besignificantly desensitized due to non-linearity of the aggressortransmitter. However, such high-Q bandpass filters can be prohibitivelyexpensive and/or introduce insertion loss that degrades transmitperformance.

In another example, a very high Q bandpass filter can be included on thevictim receiver to attenuate high power leakage coupled in from theaggressor transmitter. When the attenuation is sufficiently high, thevictim receiver is not significantly desensitized from coupling of thehigh power leakage into non-linear receive circuitry of the victimreceiver. However, such high-Q bandpass filters can be prohibitivelyexpensive and/or introduce insertion loss that degrades receiversensitivity.

RF communication systems with coexistence management are providedherein. In certain embodiments, a mobile device includes a firstantenna, a first front end system that receives an RF receive signalfrom the first antenna, a first transceiver coupled to the first frontend system, a second antenna, a second front end system that provides anRF transmit signal to the second antenna, and a second transceivercoupled to the second front end system. The second front end systemobserves the RF transmit signal to generate an RF observation signal,which is downconverted and processed by the second transceiver togenerate digital observation data that is provided to the firsttransceiver. The first transceiver downconverts the RF receive signal tobaseband, and compensates the baseband receive signal for an amount ofRF signal leakage indicated by the digital observation data.

By implementing the mobile device in this manner, compensation forsignal leakage arising from signal coupling from the second antenna tothe first antenna is provided. Thus, the mobile device operates withenhanced receiver sensitivity when the first transceiver is receivingand the second transceiver is transmitting.

In certain implementations, the first transceiver/first front end systemcan process RF signals of a different type than the secondtransceiver/second front end system. In one example, the firsttransceiver/first front end system processes cellular signals while thesecond transceiver/second front end system processes WLAN signals, suchas WiFi signals. Accordingly, in certain implementations herein,coexistence management is provided between cellular and WiFi radios.

In certain implementations, the first transceiver processes the digitalobservation data to detect direct transmit leakage. For example, thedigital observation data can include extracted samples of aggressordirect transmit leakage.

Thus, the digital observation signal can be used to compensate fordirect transmit leakage. In certain implementations, the firsttransceiver includes a spectral regrowth model used to estimate spectralregrowth leakage based on the digital observation data. In one example,the spectral regrowth model is generated by pre-distortion, forinstance, by modeling adjacent channel leakage ratio (ACLR), such asACLR2. Accordingly, multiple components of RF signal leakage can becompensated.

In certain implementations, the baseband receive signal is compensatedusing discrete time cancellation. For example, compensation can beprovided using a discrete time cancellation loop having multiple inputs.The cancellation loop can be adapted to reduce unwanted signalcomponents using any suitable cancellation algorithm, including, but notlimited to, a least mean squares (LMS) algorithm. In one embodiment, atransceiver includes a discrete time cancellation circuit including afinite impulse response (FIR) filter having coefficients adapted overtime to reduce or eliminate RF signal leakage.

The RF observation signal can be generated in a wide variety of ways. Inone example, the second front end system includes a directional coupleralong an RF signal path to the second antenna. Additionally, thedirectional coupler generates the RF observation signal based on sensingan outgoing RF signal to the second antenna. Thus, the RF observationsignal can be generated based on a forward coupled path of the seconddirectional coupler.

The second transceiver can also be implemented with circuitry forcompensating for RF signal leakage. For example, the first front endsystem can observe an outgoing transmit signal to the first antenna togenerate a second RF observation signal, which the first transceiverdownconverts to generate second digital observation data that isprovided to the second transceiver. Additionally, the second transceiverdownconverts an incoming receive signal from the second antenna togenerate a second baseband receive signal, which the second transceivercompensates for RF signal leakage based on the second digitalobservation data. Accordingly, in certain implementations, both thefirst transceiver and the second transceiver operate with coexistencemanagement.

In certain implementations, observation paths used for power control(for instance, transmit power control or TPC) and/or predistortioncontrol (for instance, digital pre-distortion or DPD) are also used forRF signal observations. By implementing the RF communication system inthis manner, circuitry is reused. Not only does this reduce cost and/orcomponent count, but also avoids inserting additional circuitry into theRF signal path that may otherwise degrade receiver sensitivity and/ortransmitter efficiency.

The coexistence management schemes herein can provide a number ofadvantages. For example, the coexistence management schemes can reducean amount of receive filtering and/or transmitter filtering, therebyrelaxing filter constraints and permitting the use of lower costfilters. Furthermore, compensation for RF signal leakage enhancesreceiver sensitivity and/or transmitter efficiency with little to noincrease in power consumption and/or componentry to RF signal paths.Moreover, multiple types of aggressor leakage components can becompensated using common cancellation circuitry, thereby providing acentralized and effective mechanism for coexistence management.

FIG. 2 is a schematic diagram of one example of signal leakage for an RFcommunication system 70. As shown in FIG. 2, the RF communication system70 includes a first transceiver 51, a second transceiver 52, a firstfront end system 53, a second front end system 54, a first antenna 55,and a second antenna 56.

Including multiple transceivers, front end systems, and antennas canenhance the flexibility of the RF communication system 70. For instance,implementing the RF communication system 70 in this manner can allow theRF communication system 70 to communicate using different types ofnetworks, for instance, cellular and WiFi networks.

In the illustrated embodiment, the first front end system 53 includes atransmit front end circuit 61, a receive front end circuit 63, and anantenna access circuit 65, which can include one or more switches,duplexers, diplexers, and/or other circuitry for controlling access ofthe transmit front end circuit 61 and the receive front end circuit 63to the first antenna 55. The second front end system 54 includes atransmit front end circuit 62, a receive front end circuit 64, and anantenna access circuit 66.

Although one example implementation of front end systems is shown inFIG. 2, the teachings herein are applicable to front end systemsimplemented in a wide variety of ways. Accordingly, otherimplementations of front end systems are possible.

RF signal leakage 69 between the first antenna 55 and the second antenna56 can give rise to a number of coexistence issues. The coexistencemanagement schemes herein provide compensation to reduce or eliminatethe impacts of such RF signal leakage.

FIG. 3A is a schematic diagram of one example of direct transmit leakagefor an RF communication system 80. The RF communication system 80includes a power amplifier 81, a victim receiver 82, a first antenna 83,and a second antenna 84.

In this example, the RF signal outputted from the power amplifier 81serves an aggressor transmit signal that is close in frequency to RFsignals processed by the victim receiver 82. Thus, direct transmitleakage from the aggressor transmit signal gives rise to a degradationin receiver sensitivity.

FIG. 3B is a schematic diagram of one example of regrowth leakage for anRF communication system 90. The RF communication system 90 includes apower amplifier 81, a victim receiver 82, a first antenna 83, and asecond antenna 84.

In this example, the power amplifier 81 receives an RF input signal,which is amplified by the power amplifier 81 to generate an RF outputsignal that is wirelessly transmitted using by the first antenna 83.Additionally, non-linearity of the power amplifier 81 gives rise tospectral regrowth in the RF output signal that is close in frequency toRF signals processed by the victim receiver 82. Thus, regrowth leakagefrom the RF output signal gives rise to a degradation in receiversensitivity.

FIG. 4A is a schematic diagram of an RF communication system 150 withcoexistence management according to one embodiment. The RF communicationsystem 150 includes a first baseband modem 101, a first transceiver 103,a first front end system 105, a first antenna 107, a second basebandmodem 102, a second transceiver 104, a second front end system 106, anda second antenna 108.

In the illustrated embodiment, the first transceiver 103 includes aleakage correction circuit 110, a transmit channel 111, and a receivechannel 114. Additionally, the first front end system 105 includes atransmit front end circuit 115, a receive front end circuit 118, and anantenna access circuit 122. Furthermore, the second transceiver 104includes a transmit channel 131, an observation channel 132, and areceive channel 134. Additionally, the second front end system 106includes a transmit front end circuit 135, an observation front endcircuit 136, a receive front end circuit 138, a directional coupler 141,and an antenna access circuit 142.

Although one embodiment of circuitry for front end systems andtransceivers is shown, the teachings herein are applicable to front endsystem and transceivers implemented in a wide variety of ways.Accordingly, other implementations are possible.

In the illustrated embodiment, the first front end system 105 receivesan RF receive signal from the first antenna 107. The RF receive signalis processed by the receive front end circuit 118 and provided to thereceive channel 114 of the first transceiver 103.

With continuing reference to FIG. 4A, baseband transmit data from thesecond baseband modem 102 is provided to the transmit channel 131 of thesecond transceiver 104, which processes the baseband transmit data togenerate an RF input signal to the transmit front end circuit 135. TheRF input signal is processed by the transmit front end circuit 135 togenerate an RF transmit signal that is provided to the second antenna108.

As shown in FIG. 4A, the directional coupler 141 senses the RF transmitsignal outputted by the transmit front end circuit 135. Additionally,the sensed signal by the directional coupler 141 is processed by theobservation front end circuit 136 and the observation channel 132 togenerate digital observation data, which is provided to the leakagecorrection circuit 110.

With continuing reference to FIG. 4A, the receive channel 114 of thefirst transceiver 103 processes the RF receive signal from the firstfront end system 105 to generate a baseband receive signal that servesas an input to the leakage correction circuit 110.

The leakage correction circuit 110 compensates the baseband receivesignal for RF signal leakage based on the digital observation data fromthe second transceiver 104. Additionally, the leakage correction circuit110 provides a compensated baseband receive signal to the first basebandmodem 101 for further processing.

In certain implementations, the leakage correction circuit 110 uses thedigital observation data to detect direct transmit leakage. For example,the digital observation data can include extracted samples of aggressordirect transmit leakage associated with RF transmit signal wirelesslytransmitted on the second antenna 108.

Thus, the digital observation signal can be used to compensate fordirect transmit leakage. In the illustrated embodiment, the leakagecorrection circuit 110 includes a spectral regrowth modeling circuit 119used to estimate spectral regrowth leakage based on the digitalobservation data. In one example, the spectral regrowth modeling circuit119 includes a spectral regrowth model generated by pre-distortion, forinstance, by modeling ACLR2.

Thus, the leakage correction circuit 110 can serve to providecompensation for multiple components of RF signal leakage, therebyproviding a centralized and effective mechanism for coexistencemanagement.

As shown in FIG. 4A, the RF observation signal is generated based on aforward coupled path to the second antenna 108. For example, the RFobservation signal is generated based on the directional coupler 141sensing an outgoing RF signal to the second antenna 108.

In certain implementations, the baseband modem 101, the firsttransceiver 103, the first front end system 105, and the first antenna107 handle a first type of RF signals, while the second baseband modem102, the second transceiver 104, the second front end system 106, andthe second antenna 108 handle a second type of RF signals. In oneexample, the first type of RF signals are cellular signals and thesecond type of RF signals are WLAN signals, such as WiFi signals. In asecond example, the first type of RF signals are WLAN signals and thesecond type of RF signals are cellular signals. Although two examples ofRF signal types have been provided, the RF communication system 150 canoperate using other RF signal types. Accordingly, other implementationsare possible.

FIG. 4B is a schematic diagram of an RF communication system 160 withcoexistence management according to another embodiment. The RFcommunication system 160 of FIG. 4B is similar to the RF communicationsystem 150 of FIG. 4A, except that the RF communication system 160illustrates a specific implementation of a leakage correction circuit.

For example, the RF communication system 160 includes a firsttransceiver 153 that includes a discrete time cancellation circuit 151.In the illustrated embodiment, the discrete time cancellation circuit151 receives digital observation data from the second transceiver 104.The discrete time cancellation circuit 151 compensates a basebandreceive signal received from the receive channel 114 to generate acompensated baseband receive signal in which spectral regrowth and/ordirect transmit leakage is reduced and/or eliminated.

The RF communication system 160 of FIG. 4B illustrates one embodiment ofcoexistence management provided by a discrete time cancellation loop.The cancellation loop can be adapted to reduce unwanted signalcomponents using any suitable cancellation algorithm. Although oneexample of a discrete time cancellation loop is shown, the teachingsherein are applicable to other implementations of coexistencemanagement. In one embodiment, the discrete time cancellation circuit151 includes a FIR filter having coefficients adapted over time toreduce or eliminate RF signal leakage.

FIG. 5 is a schematic diagram of an RF communication system 170 withcoexistence management according to another embodiment. The RFcommunication system 170 includes a first baseband modem 101, a firsttransceiver 163, a first front end system 165, a first antenna 107, asecond baseband modem 102, a second transceiver 164, a second front endsystem 166, and a second antenna 108.

In the illustrated embodiment, the first transceiver 163 includes adiscrete time cancellation circuit 151, a transmit channel 111, anobservation channel 113, and a receive channel 114. Additionally, thefirst front end system 165 includes a transmit front end circuit 115, anobservation front end circuit 117, a receive front end circuit 118, adirectional coupler 121, and an antenna access circuit 122. Furthermore,the second transceiver 164 includes a discrete time cancellation circuit152, a transmit channel 131, an observation channel 132, and a receivechannel 134. Additionally, the second front end system 166 includes atransmit front end circuit 135, an observation front end circuit 136, areceive front end circuit 138, a directional coupler 141, and an antennaaccess circuit 142.

The RF communication system 170 of FIG. 5 is similar to the RFcommunication system 160 of FIG. 4B, except that the RF communicationsystem 170 is implemented not only to provide discrete time cancellationin the first transceiver 163, but also to provide discrete timecancellation in the second transceiver 164. Thus, mutual coexistence isprovided.

For example, as shown in FIG. 5, the directional coupler 121 senses anoutgoing RF signal to the first antenna 107 to generate a sensed RFsignal that is processed by the observation front end circuit 117 andthe observation channel 113 to generate digital observation dataprovided to the discrete time cancellation circuit 152 of the secondtransceiver 164. Additionally, the incoming RF signal from the secondantenna 108 is processed by the receive front end circuit 138 and thereceive channel 134 to generate a second baseband receive signal, whichthe discrete time cancellation circuit 152 compensates for RF signalleakage using the digital observation data from the first transceiver151.

In certain implementations, the discrete time cancellation circuit 152uses the digital observation data to detect direct transmit leakage. Forexample, the digital observation data can include extracted samples ofaggressor direct transmit leakage associated with RF transmit signalwirelessly transmitted on the first antenna 107. In the illustratedembodiment, the discrete time cancellation circuit 152 also includes aspectral regrowth modeling circuit 159 used to estimate spectralregrowth leakage based on the digital observation data from the firsttransceiver 163. In one example, the spectral regrowth modeling circuit159 includes a spectral regrowth model generated by pre-distortion, forinstance, by modeling ACLR2.

FIG. 6 is a schematic diagram of an RF communication system 450 withcoexistence management according to another embodiment. The RFcommunication system 450 includes a cellular antenna 301, a WiFi antenna302, a cellular transceiver 303, a WiFi transceiver 304, a cellularfront end system 305, and a WiFi front end system 306.

Although one embodiment of an RF communication system is shown, theteachings herein are applicable to RF communication systems implementedin a wide variety of ways. For example, an RF communication system caninclude different implementations of antennas, transceivers, and/orfront end systems.

In the illustrated embodiment, the cellular transceiver 303 includes adigital baseband circuit 360 including a cellular transmit basebandsampling circuit 361, a cellular transmit power control circuit 363, adiscrete time cancellation circuit 381, a digital receiver 382, adigital switch 383, a digital distortion/ACLR generation circuit 384,and a digital mixer 385. The digital receiver 382 is coupled to acellular modem (not shown in FIG. 6). The cellular transceiver 303operates using Band 7 (B7), in this example.

The cellular transceiver 303 further includes an observation channelincluding an input amplifier 351 a, a controllable attenuator 352 a, adownconverting mixer 353 a, a low pass filter 354 a, a post-filteringamplifier 355 a, and an analog-to-digital converter (ADC) 356 a. Thecellular transceiver 303 further includes a receive channel including aninput amplifier 371, a downconverting mixer 373, a low pass filter 374,a post-filter amplifier 375, and an ADC 376. As shown in FIG. 6, anobservation local oscillator (LO) 359 generates an observation LO signalfor providing downconversion in the observation channels, while areceive LO 379 generates a receive LO signal for providingdownconversion in the receive channel.

The cellular front end system 305 includes a diplexer 311, a directionalcoupler 313, and a cellular front end module 315. The cellular front endmodule 315 includes an antenna switch module (ASM) 321, a low noiseamplifier and switches (LNA/SW) 322, a duplexer 323, a power amplifiermodule 324, a control circuit 325, and a transmit input switch 326.

With continuing reference to FIG. 6, the WiFi transceiver 304 includes adigital baseband circuit 410 including a WiFi transmit baseband samplingcircuit 411, a discrete time cancellation circuit 431, a digitalreceiver 432, a digital switch 433, a digital distortion/ACLR generationcircuit 434, and a digital mixer 435. The digital receiver 432 iscoupled to a WiFi modem (not shown in FIG. 6). The WiFi transceiver 303operates using 2.4 GHz WiFi, in this example.

The WiFi transceiver 304 further includes an observation channelincluding an input amplifier 401 a, a controllable attenuator 402 a, adownconverting mixer 403 a, a low pass filter 404 a, a post-filteringamplifier 405 a, and an ADC 406 a. The WiFi transceiver 304 furtherincludes a receive channel including an input amplifier 421, adownconverting mixer 423, a low pass filter 424, a post-filter amplifier425, and an ADC 426. As shown in FIG. 6, an observation LO 409 generatesan observation LO signal for providing downconversion in the observationchannels, while a receive LO 429 generates a receive LO signal forproviding downconversion in the receive channel.

As shown in FIG. 6, a first transceiver-to-transceiver connection 307and a second transceiver-to-transceiver connection 308 provideconnectivity between the cellular transceiver 303 and the WiFitransceiver 304. In certain implementations, the cellular transceiver303 and the WiFi transceiver 304 are a relative far distance from oneanother, and the connections 307-308 include printed circuit board (PCB)trace and/or cables (for instance, cross-UE cables).

The WiFi front end system 306 includes a diplexer 312, a directionalcoupler 314, and a WiFi front end module 316. The WiFi front end module316 includes a transmit/receive switch 341, a power amplifier 342, andan LNA 343.

With continuing reference to FIG. 6, the directional coupler 313 of thecellular front end system 305 provides sensing of an outgoing cellularsignal to the cellular antenna 301 travelling along the cellular signalpath 317. The sensed cellular signal from the directional coupler 313 isprocessed by the cellular transceiver 303 to generate first digitalobservation data for the WiFi transceiver 304. Additionally, thedirectional coupler 314 of the WiFi front end system 306 providessensing of an outgoing WiFi signal to the WiFi antenna 302 travellingalong the WiFi signal path 318. The sensed WiFi signal from thedirectional coupler 314 is processed by the WiFi transceiver 304 togenerate second digital observation data for the cellular transceiver303.

The discrete time cancellation circuit 381 of the cellular transceiver303 and the discrete time cancellation circuit 431 of the WiFitransceiver 304 operate in a manner similar to that described above withrespect to FIG. 5.

In the illustrated embodiment, the digital baseband circuit 360 of thecellular transceiver 303 includes the distortion/ACLR generation circuit384 and the digital mixer 385, which correspond to one embodiment of aspectral regrowth modeling circuit. Although one embodiment of spectralregrowth modeling is shown, the teachings herein are applicable tospectral regrowth modeling implemented in other ways.

In certain implementations, the distortion/ACLR generation circuit 384generates digital distortion/ACLR data based on the second digitalobservation data received from the WiFi transceiver 304. In certainimplementations, the distortion/ACLR data has a bandwidth greater than achannel bandwidth, for instance, at least about twice the channelbandwidth. The digital mixer 385 digitally upconverts the digitaldistortion/ACLR data to generate data estimating spectral regrowthleakage. In certain implementations, the digital mixer 385 performsdigital operations representing upconversion to intermediate frequency(IF).

In the illustrated embodiment, the digital baseband circuit 410 of theWiFi transceiver 304 includes the distortion/ACLR generation circuit 434and the digital mixer 435, which correspond to one embodiment of aspectral regrowth modeling circuit. In certain implementations, thedistortion/ACLR generation circuit 434 generates digital distortion/ACLRdata based on the first digital observation data received from thecellular transceiver 303. In certain implementations, thedistortion/ACLR data has a bandwidth greater than a channel bandwidth,for instance, at least about twice the channel bandwidth. The digitalmixer 435 digitally upconverts the digital distortion/ACLR data togenerate data estimating spectral regrowth leakage. In certainimplementations, the digital mixer 435 performs digital operationsrepresenting upconversion to IF.

FIG. 7 is a schematic diagram of an RF communication system 500 withcoexistence management according to another embodiment. The RFcommunication system 500 of FIG. 7 is similar to the RF communicationsystem 450 of FIG. 6, except that the RF communication system 500includes a different implementation of a cellular transceiver 451 and ofa cellular front end 455.

Relative to the cellular transceiver 303 of FIG. 6, the cellulartransceiver 451 of FIG. 7 includes an additional observation pathincluding a second input amplifier 351 b, a second controllableattenuator 352 b, a second downconverting mixer 353 b, a second low passfilter 354 b, a second post-filtering amplifier 355 b, and a second ADC356 b.

The cellular front end system 455 of FIG. 7 is similar to the cellularfront end system 301 of FIG. 6, except that the cellular front endsystem 455 includes a cellular front end module 465 including adirectional coupler 327 between an output of the power amplifier 324 andan input to the duplexer 323. As shown in FIG. 7, the directionalcoupler 327 provides a sensed RF signal to a first switch 466. The firstswitch 466 also selectively receives a sensed RF signal from thedirectional coupler 313 via a second switch 467.

Thus, in this embodiment, the first switch 466 selectively provides thesensed RF signal from the directional coupler 327 or the sensed RFsignal from the directional coupler 313 to the first observation channelfor processing and subsequent sampling by the baseband sampling circuit361. Additionally, the second switch 467 selectively provides the sensedRF signal from the directional coupler 313 to the second observationchannel for processing and subsequent use by the transmit power controlcircuit 363.

The sensed RF signal from the directional coupler 327 has less groupdelay effects relative to the sensed RF signal from the directionalcoupler 313. Thus, in this embodiment, the first digital observationdata provided from the cellular transceiver 451 to the WiFi transceiver304 includes additional observation information that can be used toenhance the precision of RF signal leakage compensation. Thus, enhancedreduction of RF signal leakage can be achieved.

In certain implementations, the low pass filter 354 a has a widerbandwidth that a channel bandwidth, for instance, three or more timesthe channel bandwidth. Implementing the low pass filter 354 in thismanner can aid in providing samples of ACLR, thereby aiding modeling ofspectral regrowth leakage in the distortion/ACLR generation circuit 434and/or allowing the distortion/ACLR generation circuit 434 to bebypassed. In one embodiment, the channel bandwidth of the low passfilter 354 a is controllable (for instance, digitally programmable bydigital data received over a serial interface or bus) to provideconfigurability for discrete time cancellation (for instance,flexibility to widen low pass filter bandwidth to selectivelyaccommodate ACLR sampling).

In certain implementations, the low pass filter 404 a has a widerbandwidth that a channel bandwidth, for instance, three or more timesthe channel bandwidth. Implementing the low pass filter 404 a in thismanner can aid in provide samples of ACLR, thereby aiding modeling ofspectral regrowth leakage in the distortion/ACLR generation circuit 384and/or allowing the distortion/ACLR generation circuit 384 to bebypassed. In one embodiment, the channel bandwidth of the low passfilter 404 a is controllable.

FIG. 8 is a schematic diagram of one embodiment of a mobile device 800with coexistence management. The mobile device 800 includes a digitalprocessing system 801, a first transceiver 802, a second transceiver812, a first front end system 803, a second front end system 813, afirst antenna 804, a second antenna 814, a power management system 805,a memory 806, and a user interface 807.

The mobile device 800 can be used communicate using a wide variety ofcommunications technologies, including, but not limited to, 2G, 3G, 4G(including LTE, LTE-Advanced, and LTE-Advanced Pro), 5G NR, WLAN (forinstance, WiFi), WPAN (for instance, Bluetooth and ZigBee), WMAN (forinstance, WiMax), and/or GPS technologies.

In the illustrated embodiment, the digital processing circuit 801includes a first baseband modem 821 and a second baseband modem 822. Incertain implementations, the first baseband modem 821 and the secondbaseband modem 822 control communications associated with differenttypes of wireless communications, for instance, cellular and WiFi. Asshown in FIG. 8, the first baseband modem 821, the first transceiver802, and the first front end system 803 operate to transmit and receiveRF signals using the first antenna 804. Additionally, the secondbaseband modem 822, the second transceiver 812, and the second front endsystem 813 operate to transmit and receive RF signals using the secondantenna 814. Although an example with two antennas is shown, the mobiledevice 800 can include additional antennas including, but not limitedto, multiple antennas for cellular communications and/or multipleantenna for WiFi communications.

The first front end system 803 operates to condition RF signalstransmitted by and/or received from the first antenna 804. Additionally,the second front end system 804 operates to condition RF signalstransmitted by and/or received from the second antenna 814. The frontend systems can provide a number of functionalities, including, but notlimited to, amplifying signals for transmission, amplifying receivedsignals, filtering signals, switching between different bands, switchingbetween different power modes, switching between transmission andreceiving modes, duplexing of signals, multiplexing of signals (forinstance, diplexing or triplexing), or some combination thereof.

In certain implementations, the mobile device 800 supports carrieraggregation, thereby providing flexibility to increase peak data rates.Carrier aggregation can be used for both Frequency Division Duplexing(FDD) and Time Division Duplexing (TDD), and may be used to aggregate aplurality of carriers or channels. Carrier aggregation includescontiguous aggregation, in which contiguous carriers within the sameoperating frequency band are aggregated. Carrier aggregation can also benon-contiguous, and can include carriers separated in frequency within acommon band or in different bands.

The first antenna 804 and the second antenna 814 can include antennaelements implemented in a wide variety of ways. In certainconfigurations, the antenna elements are arranged to form one or moreantenna arrays. Examples of antenna elements include, but are notlimited to, patch antennas, dipole antenna elements, ceramic resonators,stamped metal antennas, and/or laser direct structuring antennas.

In certain implementations, the mobile device 800 supports MIMOcommunications and/or switched diversity communications. For example,MIMO communications use multiple antennas for communicating multipledata streams over a single radio frequency channel. MIMO communicationsbenefit from higher signal to noise ratio, improved coding, and/orreduced signal interference due to spatial multiplexing differences ofthe radio environment. Switched diversity refers to communications inwhich a particular antenna is selected for operation at a particulartime. For example, a switch can be used to select a particular antennafrom a group of antennas based on a variety of factors, such as anobserved bit error rate and/or a signal strength indicator.

In certain implementations, the mobile device 800 operates withbeamforming. For example, the first front end system 803 and/or thesecond front end system 813 can include phase shifters having variablephase to provide beam formation and directivity for transmission and/orreception of signals. For example, in the context of signaltransmission, the phases of the transmit signals provided to an antennaarray used for transmission are controlled such that radiated signalscombine using constructive and destructive interference to generate anaggregate transmit signal exhibiting beam-like qualities with moresignal strength propagating in a given direction. In the context ofsignal reception, the phases are controlled such that more signal energyis received when the signal is arriving to the antenna array from aparticular direction.

The first transceiver 802 includes one or more transmit channels 831,one or more receive channels 832, one or more observation channels 833,and a discrete time cancellation circuit 834. Additionally, the secondtransceiver 812 includes one or more transmit channels 841, one or morereceive channels 842, one or more observation channels 843, and adiscrete time cancellation circuit 844.

The mobile device 800 of FIG. 8 illustrates one embodiment of a mobiledevice implemented with coexistence management using discrete timecancellation. Although one example of a mobile device is shown, theteachings herein are applicable a wide range of coexistence managementschemes.

The digital processing system 801 is coupled to the user interface 807to facilitate processing of various user input and output (I/O), such asvoice and data. The digital processing system 801 provides thetransceivers with digital representations of transmit signals, which areprocessed by the transceivers to generate RF signals for transmission.The digital processing system 801 also processes digital representationsof received signals provided by the transceivers. As shown in FIG. 8,the digital processing system 801 is coupled to the memory 806 offacilitate operation of the mobile device 800.

The memory 806 can be used for a wide variety of purposes, such asstoring data and/or instructions to facilitate the operation of themobile device 800 and/or to provide storage of user information.

The power management system 805 provides a number of power managementfunctions of the mobile device 800. In certain implementations, thepower management system 805 includes a PA supply control circuit thatcontrols the supply voltages of the power amplifiers of the front endsystems. For example, the power management system 805 can be configuredto change the supply voltage(s) provided to one or more of the poweramplifiers to improve efficiency, such as power added efficiency (PAE).

In certain implementations, the power management system 805 receives abattery voltage from a battery. The battery can be any suitable batteryfor use in the mobile device 800, including, for example, a lithium-ionbattery.

FIG. 9A is a schematic diagram of one embodiment of a packaged module900 with coexistence management. FIG. 9B is a schematic diagram of across-section of the packaged module 900 of FIG. 9A taken along thelines 9B-9B.

The packaged module 900 includes radio frequency components 901, asemiconductor die 902, surface mount devices 903, wirebonds 908, apackage substrate 920, and encapsulation structure 940. The packagesubstrate 920 includes pads 906 formed from conductors disposed therein.Additionally, the semiconductor die 902 includes pins or pads 904, andthe wirebonds 908 have been used to connect the pads 904 of the die 902to the pads 906 of the package substrate 920.

The semiconductor die 902 includes an RF communication systemimplemented with discrete time cancellation 941 in accordance with theteachings herein. Although the packaged module 900 illustrates oneexample of a module implemented in accordance with the teachings herein,other implementations are possible.

As shown in FIG. 9B, the packaged module 900 is shown to include aplurality of contact pads 932 disposed on the side of the packagedmodule 900 opposite the side used to mount the semiconductor die 902.Configuring the packaged module 900 in this manner can aid in connectingthe packaged module 900 to a circuit board, such as a phone board of awireless device. The example contact pads 932 can be configured toprovide radio frequency signals, bias signals, and/or power (forexample, a power supply voltage and ground) to the semiconductor die902. As shown in FIG. 9B, the electrical connections between the contactpads 932 and the semiconductor die 902 can be facilitated by connections933 through the package substrate 920. The connections 933 can representelectrical paths formed through the package substrate 920, such asconnections associated with vias and conductors of a multilayerlaminated package substrate.

In some embodiments, the packaged module 900 can also include one ormore packaging structures to, for example, provide protection and/orfacilitate handling. Such a packaging structure can include overmold orencapsulation structure 940 formed over the packaging substrate 920 andthe components and die(s) disposed thereon.

It will be understood that although the packaged module 900 is describedin the context of electrical connections based on wirebonds, one or morefeatures of the present disclosure can also be implemented in otherpackaging configurations, including, for example, flip-chipconfigurations.

Applications

Some of the embodiments described above have provided examples inconnection with mobile devices. However, the principles and advantagesof the embodiments can be used for any other systems or apparatus thathave needs for coexistence management. Examples of such RF communicationsystems include, but are not limited to, mobile phones, tablets, basestations, network access points, customer-premises equipment (CPE),laptops, and wearable electronics.

CONCLUSION

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The word “coupled”, as generally usedherein, refers to two or more elements that may be either directlyconnected, or connected by way of one or more intermediate elements.Likewise, the word “connected”, as generally used herein, refers to twoor more elements that may be either directly connected, or connected byway of one or more intermediate elements. Additionally, the words“herein,” “above,” “below,” and words of similar import, when used inthis application, shall refer to this application as a whole and not toany particular portions of this application. Where the context permits,words in the above Detailed Description using the singular or pluralnumber may also include the plural or singular number respectively. Theword “or” in reference to a list of two or more items, that word coversall of the following interpretations of the word: any of the items inthe list, all of the items in the list, and any combination of the itemsin the list.

Moreover, conditional language used herein, such as, among others,“may,” “could,” “might,” “can,” “e.g.,” “for example,” “such as” and thelike, unless specifically stated otherwise, or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or states. Thus, such conditional language is notgenerally intended to imply that features, elements and/or states are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or withoutauthor input or prompting, whether these features, elements and/orstates are included or are to be performed in any particular embodiment.

The above detailed description of embodiments of the invention is notintended to be exhaustive or to limit the invention to the precise formdisclosed above. While specific embodiments of, and examples for, theinvention are described above for illustrative purposes, variousequivalent modifications are possible within the scope of the invention,as those skilled in the relevant art will recognize. For example, whileprocesses or blocks are presented in a given order, alternativeembodiments may perform routines having steps, or employ systems havingblocks, in a different order, and some processes or blocks may bedeleted, moved, added, subdivided, combined, and/or modified. Each ofthese processes or blocks may be implemented in a variety of differentways. Also, while processes or blocks are at times shown as beingperformed in series, these processes or blocks may instead be performedin parallel, or may be performed at different times.

The teachings of the invention provided herein can be applied to othersystems, not necessarily the system described above. The elements andacts of the various embodiments described above can be combined toprovide further embodiments.

While certain embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the disclosure. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the disclosure. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the disclosure.

What is claimed is:
 1. A mobile device comprising: a first antenna and asecond antenna; a first front end system coupled to the first antenna; afirst transceiver configured to generate a first digital basebandreceive signal based on processing a radio frequency receive signalreceived from the first antenna through the first front end system, thefirst transceiver including a discrete time cancellation circuitconfigured to compensate the first digital baseband receive signal forradio frequency signal leakage based on digital observation data; asecond front end system coupled to the second antenna, and configured togenerate a radio frequency observation signal based on observing a radiofrequency transmit signal; and a second transceiver configured toprocess the radio frequency observation signal to generate the digitalobservation data, and to provide the digital observation data to thefirst transceiver.
 2. The mobile device of claim 1 wherein the discretetime cancellation circuit includes a spectral regrowth modeling circuitconfigured to estimate an amount of aggressor spectral regrowth presentin the radio frequency receive signal based on the digital observationdata.
 3. The mobile device of claim 2 wherein the spectral regrowthmodeling circuit is configured to estimate the amount of aggressorspectral regrowth based on modeling adjacent channel leakage ratio usingpredistortion.
 4. The mobile device of claim 1 wherein the secondtransceiver is configured to generate a digital observation signal basedon the radio frequency observation signal, the second transceiverincluding a baseband sampling circuit configured to sample the digitalobservation signal to generate the digital observation data.
 5. Themobile device of claim 4 wherein the baseband sampling circuit generatesthe digital observation data to reflect an amount of direct transmitleakage present in the radio frequency transmit signal.
 6. The mobiledevice of claim 1 wherein the second front end system includes adirectional coupler configured to generate the radio frequencyobservation signal.
 7. The mobile device of claim 6 wherein thedirectional coupler generates the radio frequency observation signalbased on a forward coupled path to the second antenna.
 8. The mobiledevice of claim 1 wherein the first front end system is a cellular frontend system and the second front end system is a WiFi front end system.9. The mobile device of claim 1 wherein the first front end system is aWiFi front end system and the second front end system is a cellularfront end system.
 10. The mobile device of claim 1 wherein the secondtransceiver is configured to compensate a second baseband receive signalbased on additional digital observation data from the first transceiver.11. The mobile device of claim 10 wherein the first transceiver isconfigured to receive a sensed radio frequency signal from a directionalcoupler of the first front end system, and to process the sensed radiofrequency signal to generate the additional digital observation dataprovided to the second transceiver.
 12. The mobile device of claim 11wherein the first front end system includes a duplexer, the directionalcoupler positioned between an output of the duplexer and the firstantenna.
 13. The mobile device of claim 11 wherein the first front endsystem includes a duplexer and a power amplifier, the directionalcoupler positioned between an output of the power amplifier and an inputto the duplexer.
 14. A transceiver comprising: a receive channelconfigured to process a radio frequency receive signal to generate adigital baseband receive signal; an observation channel configured toprocess a radio frequency observation signal to generate a digitalobservation signal; a baseband sampling circuit configured to sample thedigital observation signal to generate first digital observation data;an output configured to output the first digital observation data; aninput configured to receive second digital observation data; and adiscrete time cancellation circuit configured to compensate the digitalbaseband receive signal for radio frequency signal leakage based on thesecond digital observation data.
 15. The transceiver of claim 14 whereinthe discrete time cancellation circuit includes a spectral regrowthmodeling circuit configured to estimate an amount of aggressor spectralregrowth present in the radio frequency receive signal based on thesecond digital observation data.
 16. The transceiver of claim 15 whereinthe spectral regrowth modeling circuit is configured to estimate theamount of aggressor spectral regrowth based on modeling adjacent channelleakage ratio using predistortion.
 17. A method of coexistencemanagement in a mobile device, the method comprising: providing a radiofrequency receive signal from a first front end system to a firsttransceiver; processing the radio frequency receive signal to generate afirst digital baseband receive signal using the first transceiver;compensating the first digital baseband receive signal for radiofrequency signal leakage based on digital observation data using adiscrete time cancellation circuit of the first transceiver; generatinga radio frequency observation signal based on observing a radiofrequency transmit signal using a second front end system; andprocessing the radio frequency observation signal to generate thedigital observation data using a second transceiver.
 18. The method ofclaim 17 further comprising providing the digital observation data fromthe second transceiver to the first transceiver.
 19. The method of claim17 wherein compensating the first digital baseband receive signalincludes estimating an amount of aggressor spectral regrowth present inthe radio frequency receive signal based on the digital observation datausing a spectral regrowth modeling circuit.
 20. The method of claim 19wherein estimating the amount of aggressor spectral regrowth includesmodeling adjacent channel leakage ratio using predistortion.